Systems in which transactions or connections between two or more parts or stations of the system are conducted or established by means of an access code are known. Such systems include computer terminals wherein the access code is a password, bank terminals such as ATM machines wherein the access code is a personal identification number (PIN) and communications terminals such as mobile telephones wherein the access code is an electronic serial number (ESN). Typically the access code is provided by a user to an accessing part or station of the system and is verified against a duplicate version of the access code available to an accessed part or station of the system, before an authority to perform the transaction or to establish the connection between the stations or parts is given.
A disadvantage of such systems is that the security of future transactions or connections becomes seriously compromised if the access code is detected by or otherwise becomes known to unauthorised persons i.e. Persons other than the person or persons authorised to perform the transactions or establish the connection.
An object of the present invention is to provide a code based access system which alleviates the disadvantages of the prior art or at least provides the public with a choice.